This invention relates generally to food processing oven door structures and more particularly to hinge assemblies for use with such oven door structures.
Oven doors which can be removed from the hinge assemblies upon which they are mounted for opening and closing the doors are well known in the art, see for example U.S. Pat. Nos. 3,304,932; 3,398,735; 3,155,088; 3,842,542; and U.S. Pat. No. Re. 25,236. In the case of these arrangements, two hinge assemblies are conventionally employed, one at each side of the oven cavity. Each hinge assembly comprises a hinge plate attached to the front wall of the oven cabinet, a hinge arm on which the door is mounted, coupled to the hinge plate for pivotal movement with respect thereto and a roller or support arm pivotally attached to the hinge arm and passing through the hinge plate into the cabinet, alongside the oven cavity. A spring is coupled to the roller arm to bias the hinge arm toward a vertically oriented, "closed door" position.
The roller arm is normally shaped to include notches or recesses along an edge thereof in which a roller mounted at the rear of the hinge plate is received. The recesses are provided to maintain the oven door in positions of varying degrees of closure.
When the oven door is removed from the hinge arms, normally by sliding the door therefrom, the hinge arms are typically placed to a partially opened condition. Subsequent to the removal of the oven door, one or both of the hinge arms often is pulled toward the "closed door" position by a respective biasing spring because of a reduction in mass due to the removal of the door. In the last-mentioned situation, the hinge arm can engage the oven front wall which is normally coated with porcelain or a similar material, with such force that the porcelain will be chipped therefrom.
In the case of some removable oven door arrangements, pins are required to be inserted into the support arms of the hinge assemblies prior to removal to serve as a stop, whereby the oven door is held open at a predetermined position so that the door may be removed from the hinge arms. See U.S. Pat. Nos. 2,721,547 and 2,842,117 for examples of such arrangements. In the last-mentioned cases, the pins are required to hold the hinge arms at a predetermined angle with respect to the front wall of the oven cabinet as the door is removable only at that angle. While the insertion of the stop pins also indirectly alleviates the problem of the hinge arms forcibly engaging the porcelain coated front wall of the oven cabinet after the door is removed, the disadvantage in such arrangements is that the pins are inserted only when removing the oven door and thus must be removed and stored when not in use. Furthermore, so long as the pins are in place, the hinge arms extend at the prescribed angle from the front wall of the oven cabinet and could cause injury if engaged inadvertently by someone passing too near the oven.